There have been known methods of identifying the direction of an electronic component. In one example of such methods, a marker is provided on an electronic component to identify the direction thereof (e.g., Japanese Patent Application Publication No. 2008-159858 (hereinafter “the '858 Publication”)). In another example of such methods, an X ray is used to examine through an electronic component to identify the direction thereof (e.g., Japanese Patent Application Publication No. 2011-29278 (hereinafter “the '278 Publication”)).
When a marker is used to identify the direction of an electronic component as in the '858 Publication, the cost is increased because of the need of the step of forming the marker. When an X ray is used to identify the direction of an electronic component as in the '278 Publication, the cost is increased because of the need of an apparatus for emitting the X ray and a protection for blocking the X ray.